> When someone posts to this list using Cc: instead of To:, it goes out O.K.
> but the messages lacks the "To: rockbox_at_cool.haxx.se" header. Instead the
> To: header is set to whomever the original message was aimed at.

The To: header you see in mails is purely cosmetic and may in fact contain
anything the sender decides (or it can be totally absent). Relying on that
header can never be near 100% sure.

> This makes filtering with an email client more difficult, since the
> quasi-official way to catch the list emails is to search for "rockbox" in
> the To: header.

Personally, I always filter on the header "Sender:
owner-rockbox_at_cool.haxx.se" which is guaranteed to always be true on all mails
sent from by the rockbox mailing list software (using the current setup).

> Also, I just heard a rumor that such messages don't show up in the archive.
> I'll check that by searching the archive for this message in a little while.
>
> I suspect this should be considered a bug in the mailing list software.

The mailing list software is not responsible for the archiving. We have a
special "subscriber" that does the archiving, and it receives mails just like
all other subcribers and thus CC'ing the list makes no difference to it.

If some mails are not ending up in the archive, it is more probably a much
more subtle bug, possibly in the archiver (hypermail) or in my scripts that do
the initial filtering before hypermail is invoked.